Drive mechanism for tuning means



June 3, 1941.

E.. PASCHKE DRIVE MECHANISM FOB TUNING MEANS FilectDec. 6, 1938 2 Sheets-Sheet 1 INVENTOR ER/CH A CHKE BY #5 ATTORNEY Patented June 3, 1941 UNITED STATES FF'ICE DRINE IHECHANISM FOR TUNING MEANS poration of Germany Application December 6, 1938, Serial No. 2443.63

In Germany December 9,1937

2 Claims.

The present invention is concerned with the drive of tuning means of communication apparatus in which one or more points (frequencies) maybe specially marked by notches or detention points sensible to touch and adjustable in position from the outside. Mechanisms of this nature are of practical utility whenever in apparatus ashere concerned always only a limited number of fixed settings are to be used alternately or in sequence. In instances of this kind it is practical to indicate the various adjustments by the aid of notches sensible by touch on the setting means, for thisrequires less attention on the part of the user of the apparatus in eifecting the setting or tuning than in the case when he is called upon to check up on the precise or sharp adjustment on the dial.

According to the invention, the drive mechanism for tuning means in communication apparatus comprising several notch or detention points adjustable at will and sensible to touch is so constructed that upon the circumference or shell of a cylindrical body included in the drive by the mechanism, one or more rings (detention or notch rings) each having a nick or notch in which at the detention point a lever is adapted to engage with its detent, are so disposed that they are held yieldingly, that is, with spring force, upon the said body.

The invention will best be understood by reference to the following description taken in connection with the accompanying drawings in which Fig. 1 shows an elevation partly in section of a construction according to one embodiment of the invention. Fig. 2 is a section taken on line X--X of Fig. 1, and Figs. 3 to disclose a construction according to a second modification, Fig. 3 being a section taken on the line YY of Figs. 4 and 5, Fig. 5 illustrating the second notch ring from below in Fig. 3, while Fig. 4 shows any other ring.

In the embodiment shown in Figs. 1 and 2, the notch rings are yieldingly held between two metallic annular diaphragms secured upon the cylindrical body. The metallic body I of cylindrical form having an internal tooth gear running in ball bearings I9, is driven from the knob 2 which is seated upon the drive shaft 26 through the intermediary of the tooth-wheels 3 and 4. Upon the cylindrical body I are mounted the metallic diaphragms 5. Between pairs of these latter are yieldingly clamped the notch or detention rings 6. Each of these rings has a notch I in which the pawl or detent 8 of a lever Ii! pivoted at point 9 is able to engage subject to the pressure exerted by the spring I4 when the detention position has been reached. In the exemplified embodiment here shown there are by way of example provided four notch rings with the corresponding notch or detent levers. When such a notch is engaged, the number or other identification mark of the locked point ismade visible in a window or bezel, as indicated at I I. In the instance here illustrated, the notch position a is indicated. Upon the dial I2 which is also arranged upon the cylindrical body I'the particular setting of the tuning means may be read through the bezel I3.

By shifting the notch rings in relation to the cylindical body each notch point or position may be displaced so as to occupy any desired point of the dial. For this purpose there is utilized the latch I5 which is subject to pressure by the spring I Ii against the cam shaft IT. For each lever Ill there is provided a latch as indicated at I5. By turning the cam shaft I1 the latches may be lowered individually so that, if the lever has been engaged, they can drop in corresponding slots I8 of the notch lever. As a result the notch is locked in position and can be shifted by turning the tuning knob 2 in reference to the cylindrical body or drum. If the latches, by convenient rotation of the cam shaft H are lifted out of the slot I8 again, then the notch ring, due to pressure exerted by the diaphragms 5, is driven into its new adjustment by the cylindrical body I. It will thus be seen that the diaphragm pressure must be several times higher than the notch pressure.

Another exemplified embodiment is illustrated in Figs. 3 to 5. The outstanding feature of this arrangement is that each notch ring II) is split at a certain place, and that the inside diameter of the notch ring, in untensioned or relaxed state, is slightly less than the outside diameter of the cylindrical body I. The notch rings, as will thus be seen, are held fast upon the cylindrical body by virtue of inherent springiness. Referring more particularly to Fig. 3, I denotes again the cylindrical body which rotates in ball bearings I9. The transmission of the torque from the setting knob 2 to the cylindrical body or drum is the same as in the arrangement illustrated in Figs. 1 and 2. Also the levers with their detents show the same shape as in the previous mechanism. However, the latch I5 with the corresponding cam shaft I! has been dispensed with in this embodiment. The shifting of the notch or detention points is here accomplished in a different way which will be seen most clearly by reference to Figs. 4 and 5. The notches are positioned diametrically opposite the splits of the notch rings in such a way that the splits, in engaged condition, are at a definite place of the casing. Fig. 4 shows this place. I is a portion of the cylindrical body or drum and I is a portion of one of the notched rings. The latter has a split at 2|. Transversely to the split or slot 2| upon one face of the notch ring is a slot 22 in which is placed a curved spring 23 with a pin 24 the end of which, in untensioned or relaxed condition of the spring is flush with the outer surface of the shell or rim of the notched ring. In the engaged state of the notch, the said pin 24 is just opposite a pin 25 attached to a spring lever 26. By turning the cam shaft 21, the corresponding pin 25 can be guided against the pin 24. As a result, the spring 25 in the slot 22 is spread and. forces the ring apart so that the split 2| is expanded. As a result the friction of the notch ring on the cylindrical body is diminished to such extent that the cylindrical body may be continued to be shifted into a new dial position where the notch position to be adjusted is located. Instead of the spring means 23, the spreading apart of the notch ring may be effected also by the aid of a bell crank lever placed in the slot 22.

The exemplified, embodiment last disclosed offers' over the first form of construction this advantage that in ichanging a, notch or detention point, no additional friction needed to be surmounted between the cylindrical body and the notch rings, whereas adjustment in the first described arrangement is efiected only while overcoming the frictional forces set up between the diaphragm rings and the notch rings. The embodiment Figs. 1 and 2 may, however, be improved by an accessory device whereby all of the notches can be rendered inoperative simultaneously. To this end the cam shaft H is so connected that, in a definite setting, all of the latches 15 are dropped simultaneously and brought to engage behind the notch levers Ill so that the detents 8 no longer bear upon the periphery of the notch rings and engagement of the notches is precluded. In this manner adjustment of the drive mechanism at definite points is feasible without notch or detention positions being sensible to touch.

What I claim is:

1. In radio tuning mechanism, a rotary tuning shaft, a cylindrical member driven by said shaft, a plurality of split ring members each provided with a peripheral notch frictionally carried by said cylindrical member and adjustable thereon circumferentially to represent a selected station, means selectively operable to engage the notch of each of said ring members to enable the latter to be held stationary, and additional selectively operable means adapted to expand the ring members to reduce their frictional engagement with the cylindrical member, so that upon rotation of the tuning shaft the relative angular relation between each of the ring member notches and the tuning shaft may be altered.

2. In radio tuning mechanism, a rotary tuning shaft, a cylindrical member driven by said shaft, a plurality of split ring members each provided with a peripheral notch and representing a selected station, said ring members by reason of their resiliency adapted to grip the surface of the cylindrical member and be driven thereby,

and means for independently adjusting the ring members circumferentially around thecylindri-- cal member, said adjusting means comprising selectively operable members adapted to engage. the notch of each of said ring members to en able the latter to be held stationary, and selectively operable members adapted to engage the split portion of each ring member to expand the same, so that upon rotation of the tuning shaft the relative angular relation between each of the ring member notches and the tuning shaft may be altered. 1 V

ERICH PASCHKE. 

